Midnapore, March 6: The Maoists had planned to use the 250kg of explosives unearthed yesterday to blow up the Enayetpur CPM office that had successfully repelled a guerrilla attack last year, police said.

A day after stumbling on the explosives — 200kg of potassium nitrate and 50kg of sulphur — in Shirshi, West Midnapore, the police detained a couple of local residents known to be close to the Maoists.

Manoj Verma, the West Midnapore police chief, said: Preliminary information suggests the Enayetpur office was a possible target. We are verifying this information with those believed to be close to the Maoists.

The site from where the explosives were found is just 8km from the Enayetpur office. Information from our sources as well as what the detained people have told us all point to a Maoist plan to attack that office, an officer said.

The Enayetpur CPM office, now heavily fortified and teeming with armed party cadres mainly brought in from outside, has become an obstruction to Maoist movement between Salboni, Midnapore town and Orissa, the police said. There are six other similarly fortified CPM offices — in Kotwali, Salboni and Goaltore — but the Enayetpur office has posed the toughest challenge to the rebels.

Last September, the Maoists had attacked the office but had to retreat after a prolonged gun battle. Although no bodies were found, the guerrillas are believed to have suffered casualties.

The general idea was that if the Enayetpur party office fell, the CPM would vacate the other offices, a police officer said.

After the attack on the Enayetpur office, the police had set up two camps a kilometre away which, too, proved a hurdle to the Maoists movements.

The police camps are not too strong, an official said. The Maoists believe that if the Enayetpur party office goes, the police too would move from there.

The police said that a second reason for the Maoists to attack the Enayetpur office would be the possibility of looting weapons.

Of all the fortified party offices, the one in Enayetpur has the highest number of arms, an officer said.